The present disclosure relates generally to robotic submersibles and in particular to a robotic submersible capable of propulsion through both gliding and swimming.
In recent years there has been considerable interest in and development of submersible, underwater, exploratory craft in commercial, government, and military research. The underwater frontier remains a huge and much unexplored portion of the earth, with vast riches in minerals, petroleum, seabed, plants, and aquatic life. Further, underwater monitoring of chemicals, foundations, structures, and the like, is relevant to many commercial and government entities.
Development of underwater craft has remained centered mostly around submarines, although the development of underwater gliders has recently gained focus. Underwater gliders have begun to meet needs of researchers and scientists in exploring large, deep bodies of water, such as the oceans. An underwater glider utilizes its buoyancy and gravity to enable motion without any additional propulsion, and adjusts its center of gravity to achieve a certain attitude, which results in glide and thus horizontal travel. Since energy is needed only for buoyancy and center-of-gravity adjustment when switching the glide profile, underwater gliders are very energy-efficient. However, underwater gliders are large in size (for example, 1-2 meters in length), weight (for example, at least 50 kg), and cost. Further, they are slow to move and have low maneuverability making them inadequate for smaller bodies of water.
In exploration and utilization of shallower or smaller bodies of water, it becomes increasingly important that designs for underwater craft be associated with effective and reliable control systems to improve underwater maneuverability, including the ability to swim at a faster rate than the traditional underwater glider.
Thus, there is a need for a small underwater craft that can operate autonomously to monitor aquatic environments such as lakes, rivers, streams, and coastal waters. The underwater craft must be able to capture different types of data, it must be capable of propelling itself in a variety of speeds, it must have energy-saving capabilities, and it must be maneuverable underwater.